Patent GB-703868-A (GB)
Title: Improvements in or relating to hydroforming process
IPC: C10G35/14
Filed: 1951-07-25
Abstract: Naphtha vapours are passed with hot hydrogen-containing process gas through a dense fluidized bed of hydroforming catalyst in a reaction zone at 850-925 DEG F. and 100-500 lb./sq. in. at a catalyst to oil ratio by weight of from 0.5 to 3.0, substantially catalyst-free products are withdrawn overhead, a stream of catalyst is withdrawn from the bed, stripped of adsorbed hydrocarbons, regenerated by burning off carbonaceous deposits in a dense fluidized bed in a regeneration zone while controlling the temperature to below about 1200 DEG F., and recycled to the reaction zone, residual entrained catalyst is separated from the product stream, fresh naphtha feed is heated by heat exchange with the product stream and further preheated to 800-1000 DEG F. prior to feeding to the reaction zone, the product stream is further cooled to condense hydroformate which is separated from gaseous constituents which are heated to 1150-1200 DEG F. and recycled to the reaction zone.  1000-4000 c. ft. of process gas per barrel of naphtha feed are passed through the reaction zone at a space velocity of 0.15-1.5 lbs. hydrocarbon/lb. catalyst/hr.  The superficial velocity is about 0.2-0.9 ft./sec. to give a fluidized bed.  A vertical, ported, internal conduit permits flow of catalyst such as molybdena-alumina from the bed counter-current to a stream of inert stripping gas, the stripped vapours passing off with reaction products, and stripped catalyst flowing to the regenerator. Preferably not more than 40 per cent. of the air required for regeneration is used to convey the catalyst, the remainder being fed direct and, if desired, at different points along the regenerator. Regenerated catalyst leaves by an internal conduit where it is stripped of regenerating gases and fed in a stream of recycle gas back to the reactor.  The contact time of p  the catalyst with the hot recycle gas should be less than 5 secs. The residence time of catalyst in the reactor should be at least 25 times that in the regenerator.  Reaction products after passing through cyclone separators are sprayed with heavy quenching oil and the mixture centrifuged to separate a slurry of oil and catalyst from gaseous products.  The quenching oil may be a high boiling product of the hydroforming.  The hot gaseous products are used for preheating naphtha feed and recycle gas before condensing the hydroformate from hydrogen-containing gas which is returned to the process.  Controls for the flow of catalyst from the reactor and regenerator, and for the temperature in the regenerator by varying the bed depth and therefore the amount of cooling surface immersed, are provided.  The naphtha feed and recycle gas are preheated to about 800-1000 and 1150-1200 DEG F. respectively before passing to the reactor.ALSO:In a process of hydroforming naphthas using a dense fluidized catalyst in both the reaction and regeneration zones, a vertical, ported, internal conduit permits flow of catalyst such as molybdena-alumina from the reactor countercurrent to a stream of inert stripping gas, the stripped catalyst then passing to the regenerator.  Preferably not more than 40 per cent. of the air required for regeneration is used to convey the catalyst, the remainder being fed direct and, if desired, at different points along the regenerator.  Regenerated catalyst leaves by an internal conduit where it is stripped of regeneration gases.  The residence time of the catalyst in the regenerator should be at most 1/25th that in the reactor.  Reaction products, after passing through cyclone separators, are sprayed with heavy quenching oil, which may be a high boiling product of the hydroforming, and the mixture centrifuged to separate a slurry of oil and catalyst from gaseous products, catalyst being recovered from same slurry.  The temperature in the regenerator may be controlled by varying the height of the catalyst bed and, therefore, the amount of cooling surface immersed therein. Cooling coils are arranged in more widely spaced relationship near the top of the regenerator but closely spaced near the base.